<< The best source for trying to determine what was on the Ark is
Woodmorappe's book "Noah's Ark: A Feasibility Study." By considering what
the Bible might mean by 'kind' (he concludes it is not equivalent with
species), and by noting the Biblical qualifications for inclusion on the
Ark, he has estimated that there were 16000 animals on the Ark including 7
pairs for each of the 'clean' animals. >>

Woodmorappe claims on page 6 of his book on the ark "there is a very
fundamental reason why the created kind must, at minimum, be at the generic
and not specific level. The genus is the smallest division of plants and
animals that can usually be identified without scientific study (Cain 1956,
p.97). Since Scripture was written to be understood without modern
scientific training or other knowledge unavailable to the ancients (or even
outside of Scripture itself), the created kind could not possibly refer to
species, but must be broader than species."

There was a time that the genus was thought to be the smallest division of
animals that could be distinguished by people without scientific training,
and Cain's paper reflects that older view. However, there have been a number
of studies done in ethno-biology since then which show beyond any shadow of a
doubt that scientifically untrained people regularly differentiate as
different kinds, birds and all animals larger than a rat at the species
level. Woodmorappe is out of date. The biblical "kind" is more often at the
species level than the genus level, and this is especially true for the
animals Woodmorappe says were on the ark. The ark is much more crowded than
he allowed for. Until he brings his definition of "kind" up to date, his
calculations of numbers of animals and space needed on the ark are worthless.

For further details and documentation, see my paper on "kind" which includes
much of the relevant bibliography on ethno-biology: "The meaning of min,
'kind'" in Science and Christian Belief (1997) vol 9/1, pp. 47-56